Claw Clamp

ABSTRACT

A claw clamp, such as that used in conjunction with an ISO flange is illustrated. The clamp is able to hold itself on a flange assembly prior to tightening. This is accomplished by a mechanism that pressures the two halves of the clamp together prior to tightening so that the clamp can be positioned on a flange assembly and will hold itself there without intervention until tightening.

BACKGROUND

In vacuum systems several flange standards exist, and the same flangetypes are called by different names by different manufacturers andstandards organizations. Therefore, it is somewhat difficult to identifycommon terminology to refer to common flange types.

The ISO standard quick release flange is known by the names Quick Flange(QF), Klein Flange (KF) or NW, sometimes also as DN. The KF designationhas been adopted by the International Organization for Standardization(ISO), the Deutsches Institut fur Normung (DIN) and Pneurop, a lobbyinggroup for the European compressor and vacuum pump industry. KF flangesare made with a chamfered back surface that attached with a circularclamp and an elastomeric o-ring that is mounted in a metal centeringring.

The ISO large flange standard is known as an LF, LFB, MF or sometimesjust an ISO flange. FIG. 1 illustrates a representative ISO flange. Theflanges 100 are usually joined by a centering ring 110 and anelastomeric o-ring 120. An extra optional spring-loaded circular clampor spacer ring 130 is often used around the large diameter o-rings toprevent them from rolling off from the centering ring during mounting.

The ISO large flanges come in at least two varieties. The ISO-K (or ISOLF) flanges shown in FIG. 1 are typically joined with double claw clamps140 which clamp to a groove 150 on the tubing side of the flange. FIG. 2illustrates the ISO-F (or ISO LFB) flanges 230 which have holes forattaching the two flanges with bolts. As illustrated in FIG. 2, twotubes with ISO-K and ISO-F flanges can be joined together by clampingthe ISO-K side with single claw clamps, such as example single clawclamp 240, which are each bolted to a hole on the ISO-F side.

Returning to FIG. 1, the double claw clamp 140 has first half 160 andsecond half 170 joined by bolt 180. A washer 190 is usually used on thebolt. First half 160 typically has a projection 200 that allows theclaws of the clamp to apply pressure to the flanges 100 as bolt 180 istightened.

Assembling two flanges together with the centering ring, o ring, spacerring, and double claw clamps can be difficult, with never enough handsto hold and tighten everything together.

SUMMARY

The following presents a simplified summary of the disclosure in orderto provide a basic understanding to the reader. This summary is not anextensive overview of the disclosure and it does not identifykey/critical elements of the invention or delineate the scope of theinvention. Its sole purpose is to present some concepts disclosed hereinin a simplified form as a prelude to the more detailed description thatis presented later.

The present examples describe a clamp that is able to hold itself on aflange assembly in a properly aligned fashion prior to tightening. Thisis accomplished by a mechanism that draws or locks the two halves of theclamp together prior to tightening so that the clamp can be positionedon a flange assembly and will hold itself there without interventionuntil tightening.

Many of the attendant features will be more readily appreciated as thesame become better understood by reference to the following detaileddescription considered in connection with the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

The present description will be better understood from the followingdetailed description considered in connection with the accompanyingdrawings, wherein:

FIG. 1 is a prior art figure showing a double claw clamp and an ISOflange assembly.

FIG. 2 is a prior art figure showing a single claw clamp.

FIG. 3 illustrates a first example.

FIG. 4 illustrates a second example.

FIG. 5 illustrates a third example.

FIG. 6 illustrates a fourth example.

Like reference numerals are used to designate like parts in theaccompanying drawings.

DETAILED DESCRIPTION

The detailed description provided below in connection with theaccompanying drawings is intended as a description of the presentexamples and is not intended to represent the only forms in which thepresent examples may be constructed or utilized. The description setsforth at least some of the functions of the examples and/or the sequenceof steps for constructing and operating examples. However, the same orequivalent functions may be accomplished by different examples.

Turning to FIG. 3 a first example is presented. This example shows adouble claw clamp that can be used to clamp an ISO flange assembly. Theclamp has a first half 300 and second half 310. As illustrated in FIG.3, first half 300 and second half 310 may be adapted to engage an ISOflange assembly, such as the flange assembly illustrated in FIG. 1.First half 300 and second half 310 may also be adapted to engage othertypes of flange assemblies if desired. First half 300 and/or second half310 may also include a step or projection (not shown) such as projection200 illustrated in FIG. 1. As illustrated in FIG. 3, first half 300 andsecond half 310 may include areas that are textured and/or hollowed out320, 330 to afford a better grip when the two halves are grasped to drawthem apart.

Examples described herein may include means for pressuring the firsthalf and second half toward each other to hold the clamp in position fortightening. In FIG. 3, such pressuring means may comprise spring 340. Inthe example illustrated in FIG. 3, spring 340 is held in place by rod350, which has threads 355 on one end which will pass through hole 360of first half 300 and engage corresponding threads cut into second half310. In the example in FIG. 3, hole 360 is sized such that rod 350(except for enlarged end 370) will pass through hole 360 while spring340 will not. One end of spring 340 will engage first half 300 withoutpassing through hole 360, while the other end of spring 340 is held inplace by enlarged end 370 of rod 350. Hole 360 may include a largerportion and a smaller portion so that spring 340 is recessed into firsthalf 300, while not completely passing through hole 360.

Although in FIG. 3 the means for pressuring the first half and secondhalf toward each other to hold the clamp in position for tightening isillustrated as comprising a spring, which is held internal to first half300, other arrangements are also possible. For example, a spring orother such device may be held externally to first half 300 and secondhalf 310 so that as the two halves are drawn apart, a force pressuringthe two halves together is generated. As another example, the roles ofthe first half and second half can be reversed such that a spring, othermechanism, is held internal to second half 310 rather than first half300. As yet a further example, a magnet or other magnetic device may beused to create a force pressuring the two halves together. Othermechanisms that create either tension or compression between the twohalves so as to pressure them together may also be employed. All that isimportant to the invention is that a force is created that tends topressure the two halves together at least as the two halves are drawnapart. In one example, the two halves are typically drawn apart by aninstaller (a person) while installing the clamp on a flange assembly.The pressuring means tends to pressure the two halves back together andhold the clamp on the flange assembly when the clamp is released by theinstaller.

Examples described herein may also include means for tightening theclamp. This tightening means is typically separate and distinct from thedrawing means. In the example illustrated in FIG. 3, such tighteningmeans may comprise rod 380. As illustrated in FIG. 3, rod 380 typicallyhas threads at one end and a mechanism to enable the rod to be rotatedor tightened at the other. In FIG. 3, such a mechanism is illustrated byknob 395. However, a hex bolt head or other mechanism can also be used.The threads on rod 380 are designed to pass through hole 385 and engagethreads cut into second half 310. Some mechanism, such as a washer (notshown), the enlarged hex head of a bolt (not shown), a knob (like knob395), and/or shoulder 390 is designed to engage first half 300 so thatas rod 380 is rotated, the clamp is tightened sufficiently for theflange assembly.

Examples described herein may also include means to prevent pivoting ofthe first half relative to the second half. In the example illustratedin FIG. 3, no further structure is required for such means. Rod 350 androd 380 both pass through first half 300 and engage second half 310.Thus, these rods will prevent first half 300 from pivoting relative tosecond half 310. In other embodiments, such as those illustrated in FIG.5 or FIG. 6, other structure may perform this function.

Turning now to FIG. 4, another example is illustrated. The example inFIG. 4 includes first half 400 and second half 410. Although notillustrated, first half 400 and second half 410 may also includetextured and/or hollowed out, although such is not required.

As previously mentioned, examples described herein may include means forpressuring the first half and second half toward each other to hold theclamp in position for tightening. In FIG. 4, such means may comprisespring 420. In the example illustrated in FIG. 4, spring 420 is held inplace by optional washer 430 and rod 440, which has threads 445 on oneend which will pass through hole 450 of first half 400 and engagecorresponding threads cut into second half 410. In the example in FIG.4, hole 450 is sized such that rod 440 (except for enlarged end 460)will pass through hole 450 while spring 420 will not. One end of spring420 will engage first half 400 without passing through hole 450, whilethe other end of spring 420 is held in place by enlarged end 460 of rod440. Hole 450 may include a larger portion and a smaller portion so thatspring 420 is recessed into first half 400, while not completely passingthrough hole 450.

Although in FIG. 4 the means for pressuring the first half and secondhalf toward each other to hold the clamp in position for tightening isillustrated as comprising a spring, which is held internal to first half400, as previously mentioned other arrangements are also possible. Forexample, a spring or other such device may be held externally to firsthalf 400 and second half 410 so that as the two halves are drawn apart,a force pressuring the two halves together is generated. As anotherexample, the roles of the first half and second half can be reversedsuch that a spring, or other pressuring means, is held internal tosecond half 410 rather than first half 400. As yet a further example, amagnet or other magnetic device may be used to create a force thatpressures the two halves toward each other as they are drawn apart. Anexample of such magnet or magnetic forces may be created by embedding amagnet into face 465 of first half 400 and a corresponding magnet orsteel plate in corresponding face 470 of second half 410. As the twohalves are brought into proximity to each other, a magnetic force willkeep the clamp on a flange assembly without intervention until the clampcan be tightened. Other mechanisms that pressure the two halve towardeach other as the two halves are drawn apart may also be employed. Allthat is important to the invention is that a force pressures the twohalves toward each other as the two halves are drawn apart.

Examples described herein may also include means for tightening theclamp. In the example illustrated in FIG. 4, such means may comprise rod440. As illustrated in FIG. 4, and previously described, rod 440 hasthreads at one end 445 and a mechanism 460 that allow the rod to berotated at the other. In FIG. 4, such a mechanism is illustrated by ahex bolt although a knob or other mechanism can also be used. As rod 440is rotated, the clamp is tightened sufficiently for the flange assembly.

As described above, in the example in FIG. 4, the means for pressuringand the means for tightening are combined to use common structures tohelp reduce the number of parts. However, the tradeoff is that if ameans to prevent pivoting of the first half relative to the second halfis desired, additional structures are used. In FIG. 4, no such means toprevent pivoting is illustrated.

Turning to the example in FIG. 5 and the example in FIG. 6, means toprevent pivoting of the first half relative to the second half areillustrated that can be used with an appropriate example. In FIG. 5 andFIG. 6, only the means to prevent pivoting of the first half relative tothe second half is discussed. However, such an example may include otherstructures and/or means such as those previously described inconjunction with FIG. 3 and/or FIG. 4, or others.

In FIG. 5, means to prevent pivoting of the first half relative to thesecond half comprises projection 520 of first half 500 which engagesslot 530 of second half 510.

In FIG. 6, means to prevent pivoting of the first half relative to thesecond half comprises structure 620 of first half 600 which engages slot630 of second half 610.

In view of the many possible embodiments to which the principles of thepresent invention and the forgoing examples may be applied, it should berecognized that the examples described herein are meant to beillustrative only and should not be taken as limiting the scope of thepresent invention. Therefore, the invention as described hereincontemplates all such embodiments as may come within the scope of thefollowing claims and any equivalents thereto.

1. A clamp comprising: a first half to engage a groove within a firstflange; a second half to engage a groove within a second flange; meansfor pressuring the first half and second half of the clamp in positionfor tightening; and means for tightening the clamp.
 2. A clamp as inclaim 1 wherein the means for pressuring the first half and second halftogether comprises a spring.
 3. A clamp as in claim 2 further comprisinga rod passing through the first half and being fixed to the second half,the rod holding the spring against the first half such that when thefirst and second halves are drawn apart, an increasing pressure isproduced.
 4. A clamp as in claim 1 wherein the means for tighteningcomprises a thumb knob that allows the clamp to be tightened withouttools.
 5. A clamp as in claim 1 wherein the means for pressuring and themeans for tightening together prevent the first half and the second halffrom pivoting relative to each other.
 6. A clamp as in claim 1 whereinthe means for tightening comprises a rod having threads, the rod passingthrough the first half and engaging threads in the second half, the rodretaining the means for pressuring such that when the first and secondhalves are drawn apart, an increasing pressure is produced.
 7. A clampas in claim 6 wherein the means for pressuring comprises a spring.
 8. Aclamp as in claim 7 wherein the means for tightening further comprises athumb knob.
 9. A clamp comprising: a first half configured to engage agroove within a first flange; a second half configured to engage agroove within a second flange; a rod having threads, the rod passingthrough the first half and engaging threads in the second half; and aspring positioned such that drawing the first half away from the secondhalf compresses the spring.
 10. A clamp as in claim 9 wherein the springis further positioned to pressure the first half toward the second halfwhen no external forces are acting on the clamp.
 11. A clamp as in claim9 further comprising means to prevent pivoting of the first halfrelative to the second half.
 12. A clamp as in claim 11 wherein themeans to prevent pivoting comprises at least one structure fixed to oneof either the first or second half and movably engaged with the other ofthe first or second half.
 13. A clamp as in claim 9 wherein the springis positioned around the rod.
 14. A clamp as in claim 13 wherein the rodhas affixed thereto a thumb knob allowing the clamp to be tightenedwithout tools.
 15. A clamp as in claim 9 further comprising a secondrod, wherein the spring is positioned around the second rod.
 16. A clampas in claim 15 wherein the rod has affixed thereto a thumb knob allowingthe clamp to be tightened without tools.
 17. A clamp as in claim 9wherein the rod has affixed thereto a thumb knob.
 18. A clamp as inclaim 9 wherein the rod is a bolt.
 19. A clamp comprising: a first halfconfigured to engage a groove within a first flange; a second halfconfigured to engage a groove within a second flange; a rod passingthrough the first half and being fixed to the second half; a springpositioned around the rod such that one end engages the first half andthe second end engages the rod so that drawing the first half away fromthe second half compresses the spring; and a second rod passing throughthe first half and engaging the second half, such that when the rod ismanipulated, the first half is drawn toward the second half to tightenthe clamp.
 20. A clamp as in claim 19 wherein the first rod and thesecond rod and the first half and the second half are configured suchthat the first half and the second halve are unable to pivot relative toeach other.